1. Field of the Invention
The present invention relates to annular bore seals for use in pipe connectors and swivel joints, among other devices. More particularly, the invention relates to such a seal which includes an extended wear sleeve for protecting the adjacent areas of the pipe connectors and swivel joints that are subject to erosive wear.
2. Description of Related Art
Bore seals are used to provide a fluid-tight seal between adjoining pipes or members of swivel joints and pipe connectors. U.S. Pat. No. 4,930,791, which is owned by the assignee hereof, discloses a bore seal assembly mountable within a seal pocket formed in the adjacent ends of the pipes to be sealed. This bore seal assembly comprises a cylindrical seal sleeve having a pair of annular sealing lips for sealing against corresponding sealing surfaces formed in the seal pocket, a cylindrical finger spring mounted within the bore of the seal sleeve for urging the seal sleeve against the seal pocket, and a cylindrical wear sleeve mounted within the bore of the finger spring to protect the seal sleeve and finger spring against erosion and hold the entire bore seal assembly together. The finger spring comprises an annular central section and a plurality of fingers extending axially therefrom around the entire circumference of the finger spring. In addition, the wear sleeve includes an annular rib extending radially outwardly from the wear sleeve for engaging the central section of the finger spring. In this manner, the fingers of the finger spring are permitted to flex radially inwardly adjacent the central section as the bore seal assembly is installed and impart a preload force which urges the sealing lips against the sealing surface of the seal pocket.
In certain applications, the inner diameter area of adjoining pipe members adjacent the bore seal is subject to substantial erosive wear. For example, in swivel joints where the wall section becomes gradually thinner due to erosion until a minimum wall thickness is reached. The inner diameter area under the male ball race is particularly susceptible to erosion. When erosion reduces the wall section to its minimum acceptable level, the swivel joint must be replaced. This increases the operating costs of the system in which the swivel joint is employed.